CC BY-NC-ND 4.0 · Rev Bras Ortop (Sao Paulo) 2020; 55(06): 708-714
DOI: 10.1055/s-0040-1702951
Artigo Original
Quadril

Dual mobility cup in total hip arthroplasty. The experiense of the university hospital

Article in several languages: português | English
1  Grupo de cirurgia do quadril e joelho, Serviço de Ortopedia e Traumatologia, Hospital Universitário, Universidade Federal do Maranhão, São Luís, Maranhão, Brasil
› Author Affiliations
 

Abstract

Objective To evaluate the incidence of prosthetic instability in a consecutive series of 42 cases of total hip arthroplasty using dual mobility cup.

Methods A retrospective study of 38 patients undergoing primary or revision total hip arthroplasty (THA) using the acetabular dual-mobility cup (DMC) implant between January 2012 and January 2018. The rates of complications and instability after surgery were evaluated.

Results In total, 42 arthroplasties were performed in 38 patients, with a minimum follow-up of 16 months. The mean age of the sample was 60 years. In 38 cases, we used a cementless DMC, and, in the other 4 cases, a cemented DMC. There were no cases of early or late instability.

Conclusion The series herein presented proves the good result of the DMC in cases of primary arthroplasty, complex and complicated cases of failed osteosynthesis of proximal femoral fractures, and revision for THA instability. The absence of episodes of prosthetic instability and complications in complex cases of primary and revision THA increases the confidence in this concept.


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Introduction

Total hip arthroplasty (THA) is one of the most clinically-successful and cost-effective interventions in health care of the last century.[1] [2] However, despite the continuous improvement in surgical technique and implant development, the overall revision THA (rTHA) rate remains unchanged, with instability review as the main cause.[1] [3]

Instability occurs in ∼ 1% of cases of THA in the first month after surgery, and, after 1 year, the risk of dislocation increases at a linear rate to a cumulative risk of 7% after 20 years.[4] [5] The literature suggests that more than a half of all dislocations occur within the first 3 postoperative months,[6] and more than 75% occur within 1 year.[7] Instability after THA has a considerably negative effect on the quality of life, especially if it is recurrent.[8]

Several factors have been proposed to influence the stability of THA, but many questions remain unsolved.[3] [5] [9] The instability may be classified according to the predisposing cause: factors related to the patient, to the surgical act, and factors intrinsic to the implant. Among the factors related to the patient, we can mention advanced age,[3] [7] American Society of Anesthesiologists (ASA) score ≥ 3,[9] [10] the female gender,[9] [11] femoral-neck fracture (FNF),[3] [9] osteonecrosis of the femoral head (ONFH),[3] [9] [12] developmental dysplasia of the hip (DDH),[9] neuromuscular disorders,[6] [9] previous hip surgery,[9] [13] and rTHA.[5] [6] Among the factors related to the surgery are the orientation of the components,[11] [13] the surgical posterolateral approach,[3] [13] [14] [15] and the surgical volume.[7] [12] [15] Among the factors intrinsic to the implant are the diameter of the femoral head and the head-neck ratio[3] [16] ([Table 1]).

Table 1

Patient

Surgeon

Implant

Advanced age ≥ 75 years

Orientation of the components

Femoral-head diameter

Female gender ≥ 70

Surgical volume

Head-neck ratio

American Society of Anesthesiologists score ≥ 3

Posterolateral approach

Femoral-neck fracture

Osteonecrosis of the femoral head

Developmental dysplasia of the hip

Neuromuscular disorders

Prior hip surgery

Revision total hip arthroplasty

There is a little consensus on the best method to prevent and treat instability, particularly in high-risk patients.[4]

More than 40 years ago, Gilles Bousquet and his engineer André Rambert[19] [25] had the genius idea of marrying the concept of low-friction arthroplasty (LFA), developed by Sir John Charnley in 1972,[17] and its longevity benefits to the large heads (metal-metal) of MacKee and Watson-Farrar,[18] providing greater stability. In 1976, based on this concept, the idea of the dual-mobility cup (DMC) came to be[19] ([Fig. 1]).

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Fig. 1 Three-joint system: a socket, a free polyethylene liner and a head. Source: https://link.springer.com/article/10.1007/s00264-017-3420-7.

The objective of the present study was to describe our experience with the use of the DMC in a series of cases, with a minimum follow-up of 16 months.


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Materials and Methods

We performed a retrospective study of 38 patients undergoing THA or RTHA, in which acetabular DMC was used in the prevention or treatment of postoperative instability. The present study was approved by the Ethics in Research Committee of our Institution under the number 1,786,868. The study included consecutive cases of DMC implant performed at our institute from January 2012 to January 2018. All cases were submitted to the same surgery, through the posterolateral approach and under spinal anesthesia. All patients undergoing primary THA or rTHA with DMC were included.

The preoperative patient data were collected retrospectively and prospectively during the regular follow-up.


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Results

Between January 2012 and January 2018, 42 arthroplasties were performed in 38 patients, with a minimum follow-up of 16 months. The mean age of the sample was 60 years old (range: 17–90 years). There were 21 (55.2%) males and 17 (44.8%) females. As for etiology, there were 14 (36.8%) procedures due to primary osteoarthritis, and 28 (73.2%) due to a variety of causes – 12 due to ONFH (2 due to alcohol abuse, 2 due to FNF, 3 posttraumatic, 2 due to sickle-cell anemia, 2 due to corticoid use, 1 due to radiotherapy); 5 due to an acute FNF in the elderly; 2 for rheumatoid arthritis; 2 for failure of the osteosynthesis in proximal femur fracture; 2 for pseudarthrosis of the femoral neck; 2 due to DDH; and 1 due to proximal femoral epiphysiolysis (PFE). There also were 3 cases of rTHA (1 case of instability; 1 case of aseptic loosening ;and 1 case of conversion of failed hemiarthroplasty to THA).

In 38 (90.4%) cases, we used cementless DMC ([Fig. 2]), and in 4 (9.6%) cases, cemented DMC ([Fig. 3]).

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Fig. 2 Anteroposterior pelvic radiograph of a 45-year-old female, with bilateral osteonecrosis of the femoral head (ONFH) (A), and postoperative cementless bilateral dual-mobility cup (DMC) (B).
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Fig. 3 Preoperative anteroposterior pelvic radiograph of a 69-year-old female with femoral neck pseudarthrosis (A), and postoperative cemented DMC (B).

The preoperative demographic data are listed in [Table 2].

Table 2

Age

17–90 years

Gender

Male: 21

Female: 17

American Society of Anesthesiologists score

I: 5

II: 16

III: 19

Preoperative diagnosis

Primary osteoarthritis: 14

Osteonecrosis of the femoral head: 12

Acute femoral-neck fracture: 5

Osteosynthesis failure: 2

Revision total hip arthroplasty: 3

Rheumatoid arthritis: 2

Pseudoarthrosis of the femoral neck: 1

Developmental dysplasia of the hip: 1

Proximal femoral epiphysiolysis: 1

The postoperative data collection included surgical side, surgical type of THR, cemented or cementless DMC, postoperative intensive care unit (ICU), length of stay (LOS) (in nights) after surgery, and average follow-up ([Table 3]).

Table 3

Surgical side

Right: 15

Left: 21

Bilateral: 3

Dual-mobility cup

Cemented: 4

Cementless: 38

Total hip arthroplasty

Primary: 39

Revision: 3

Blood transfusion

Yes: 19

No: 23

Intensive care unit

Yes: 20

No: 22

Length of stay (nights after surgery)

4

Average follow-up

12–74 months

In the routine controls, we performed radiographs in the immediate postoperative period in all cases. In total, 2 patients (5.5%) were identified with stable periprosthetic fractures of the femur (Vancouver type B1), which were treated conservatively and successfully ([Fig. 4]).

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Fig. 4 Preoperative anteroposterior pelvic radiograph of a 56-year-old male with left-sided ONFH (A) and postoperative cemented DMC with stable Vancouver-type-B1 periprosthetic fracture of the femur(B). The fractures were conservatively and successfully treated.

Another patient presented partial paralysis of the fibular nerve, evolving with complete resolution after 8 postoperative weeks. There were no cases of postoperative deep venous thrombosis or infection.

There was a case of death after 2 years of surgery in a patient submitted to THR due to FNF. He was well since the surgery until the last evaluation.


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Discussion

Total hip arthroplasty has been performed since the 1960s, and has significantly improved the quality of life of patients suffering from osteoarthritis of the hip.[1] However, despite the high success rate, instability after THA remains a problem that is difficult to manage for the patient and the surgeon.[2] [3] [4] [5]

Bozic et al.[4] evaluated device failures in 51,345 rTHA procedures performed in the United States October 1, 2005, and December 31, 2006. The most common cause of rTHA was instability (22.5%). Revision due to dislocation accounted for 9% of all revisions of primary THAs in the Swedish Hip Arthroplasty Register. It is the second most common reason for revision. The Australian National Joint Replacement Registry reported a proportion of 26% rTHA due to dislocation in 2011.[3] In contrast to the literature, the incidence of THA instability in France is the fifth cause of rTHA.[9] [20] [21]

Dislocation after THA is multifactorial ([Table 1]). The factors related to the patient are unchanging. However, the factors related to the choice of surgical approach and the type of implant involve the surgeon. Avoiding hip dislocation after THA is the best strategy. Over the past decade, we have seen an exponential increase in published articles on the use of THA with DMC. Many of these articles show very low dislocation rates, or even the absence of this complication.[3] [5] [9] [19] [20] [21] [22] [23] [24] The DMC device was created in France in 1976 to increase the stability and enhance joint mobility with low-friction.[19]

We have been using the DMC since January 2012. Initially, we used it only in elderly patients with FNF and in patients at high risk for instability after THA. However, as we became more familiar with the technique, and acquired more knowledge on biomechanics and DMC principles, the indications were gradually extended. We currently recommend the DMC for patients of any age or with any diagnosis, as we have not observed any problems the at follow-up. The absence of instability is confirmed by the results of the literature.[16] [24]

For Woo and Morrey,[14] the risk of dislocation is 2 times greater for women when compared with men. Coventry[11] observed that this rate was 3 times greater for women when compared with men 5 years after surgery. For Bozic et al.,[4] rTHA procedures were most commonly reported in the age group between 75 and 84 years (27.0%). For Guyen et al.,[9] gender alone is not enough to indicate the systematic use of the DMC device. They considered the female gender a risk factor for dislocation, when associated with ages 70 years or older. In this study, there were 17 females. The ASA score has been identified as a good risk for the dislocation variable, because it is closely-related to multisystem disease that increases with age and complicates muscle recovery. The authors observed that scores ≥ 3 meant a significant risk for dislocation.[10] In the present study, 42.8% (19) of the patients had ASA scores ≥ 3. All patients had a good evolution.

In 10,500 conventional THAs performed at the Mayo Clinic, 331 (3.2%) cases of instability were observed. Cross correlations of the data were performed, using multivariate analysis. The dislocation rate was of 2.3% after an anterolateral approach, and of 5.8 percent after a posterolateral approach.[14] The demographic factors, the operative approach, and the femoral-head diameter were analyzed to determine their effect on the risk of a first-time dislocation in 21,047 primary THAs. The cumulative 10-year rate of dislocation was of 3.1% following anterolateral approaches, and of 6.9% following posterolateral approaches.[16] In a case-control study of 213 hips, no dislocations were found in primary THAs using a posterior approach, whereas 5 dislocations occurred in patients operated with a conventional 28-mm metal head.[20] All cases in these series were treated by the posterolateral approach with DMC and 28-mm metal heads. There were no cases of instability.

Another group with risk of instability are the patients previously operated on the hip.[9] [12] [14] In the case of complex THAs, the dislocation rate ranged from 5% to 30% because of the bone loss and the compromised muscles and soft tissues around the hips.[16] The use of DMC in cases of complex THA has shown a dislocation rate from 1% to 10% at an 8-year follow-up.[25] In the present study, there were 7 (16.6%) cases of THA in patients with previous hip surgery, including 2 cases (5,5%) of osteosynthesis failure in proximal femur fractures. In all cases, there was a good evolution.

The reported incidence of dislocation after rTHA is as high as 22.5% to 39%,[4] [5] [6] and in some cases a new revision surgery is an inevitable procedure, particularly in patients with multiples risk factors for instability. The best strategy is the adequate choice of surgical approach and implants for the prevention of trouble in the future.[5] In the present study, there was only one case of rTHA due to instability. However, this patient had several risk factors to evolve with instability after the new rTHA procedure. The patient was female, had rheumatoid arthritis, was using corticosteroids, had a history of alcohol abuse, had already been operated on three times, and had a low muscle reserve and low bone stock. A metal DMC was cemented into a well-fixed acetabular shell. This is another advantage of the DMC device: it is versatile. The patient had a good evolution, without instability.

In many studies, the diagnosis of FNF is associated with an increased risk of rTHA due to dislocation.[3] [9] [12] Lu-Yao et al. found a dislocation rate of 10.7% in patients with FNF treated with THA.[26] Tarasevicius et al.[23] compared DMC implants with conventional THA for FNF treatment. After 1 year of postoperative follow-up, no dislocations were reported in the DMC group, compared with 8 (14.3%) dislocations in the conventional THA group. In a similar study, Adam et al.[27] reported 3 (1.4%) dislocations at a 9-month follow-up in 214 patients treated with DMC due to FNF. There were no cases of instability in this sample.

Although the medical literature presents robust evidence regarding the safety of the DMC system in the prevention of instability, we have observed two major problems: Intraprosthetic dislocation (IPD) and implant survival in younger patients. Dislocation is a specific complication found in cases of DMC implantation, and it is induced by the loss of the polyethylene retaining edge, resulting in the separation of the femoral head from the polyethylene lining. However, the articles[9] [19] [28] show that this complication occurred with the first-generation 22-mm head implants and traditional polyethylene. Based on the design of the implant, the IPD rates may vary from 1.9% to 5.2% regarding the older generation of DMC models, with a median follow-up of 4 to 17 years.[28] Currently, this complication is rare with the use of cross-linked polyethylene associated with the use of 28-mm heads.[24] [29] Regarding implant survival in younger patients, there are numerous studies showing similar survival rates as those of conventional implants.[3] [5] [19] [20] [22] [24] [25] [27] There were no cases of dislocation or wear in the present case series.

The statistical power of the present study is certainly limited by the small sample size.


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Conclusion

The present case series proves the good results of the DMC in primary THA and rTHA. The excellent survival rate and the absence of episodes of prosthetic instability increase the confidence in this concept.


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Conflito de interesses

Os autores declaram não haver conflito de interesses.


Endereço para correspondência

Raul Frankllim Carvalho Almeida, Master
Chefe do Grupo de cirurgia do quadril e joelho, Serviço de Ortopedia e Traumatologia do Hospital Universitário da Universidade Federal do Maranhão (HU-UFMA)
Rua Barão de Itapary, 270, 65020-070, Centro, São Luís, Maranhão
Brazil   

Publication History

Received: 20 August 2019

Accepted: 12 December 2019

Publication Date:
08 June 2020 (online)

© 2020. Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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Zoom Image
Fig. 1 Sistema de dupla mobilidade: componente acetabular, polietileno móvel e a cabeça femoral. Fonte: https://link.springer.com/article/10.1007/s00264-017-3420-7.
Zoom Image
Fig. 1 Three-joint system: a socket, a free polyethylene liner and a head. Source: https://link.springer.com/article/10.1007/s00264-017-3420-7.
Zoom Image
Fig. 2 Radiografia anteroposterior de mulher de 45 anos, com osteonecrose da cabeça femoral (ONCF) bilateral (A), acetábulo de dupla mobilidade não-cimentado (B).
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Fig. 3 Radiografia pré-operatória pélvica anteroposterior de mulher de 69 anos, com pseudoartrose do colo femoral (A), e acetábulo de dupla mobilidade cimentado cimentada no pós-operatório (B).
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Fig. 4 Radiografia pré-operatória pélvica anteroposterior de homem de 56 anos, com ONCF esquerda (A), e radiografia pós-operatória de acetábulo de dupla mobilidade não-cimentado com fratura de fêmur periprostética estável, Vancouver tipo B1 (B). As fraturas são tratadas de forma conservadora e com sucesso.
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Fig. 2 Anteroposterior pelvic radiograph of a 45-year-old female, with bilateral osteonecrosis of the femoral head (ONFH) (A), and postoperative cementless bilateral dual-mobility cup (DMC) (B).
Zoom Image
Fig. 3 Preoperative anteroposterior pelvic radiograph of a 69-year-old female with femoral neck pseudarthrosis (A), and postoperative cemented DMC (B).
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Fig. 4 Preoperative anteroposterior pelvic radiograph of a 56-year-old male with left-sided ONFH (A) and postoperative cemented DMC with stable Vancouver-type-B1 periprosthetic fracture of the femur(B). The fractures were conservatively and successfully treated.